It is known to use dipole, quadralpol, saddle and racetrack type superconducting magnets for EMTs. The conventional EMTs may however be too big and too heavy to gain enough thrust for full-scale ships because of a low magnetic field of such magnets and it being difficult to construct the magnets. The magnetic field must be so strong, e.g., 10 to 20 Teslas, to obtain enough propulsive efficiency for EMT ships. The EMT having such a strong magnetic field may be a huge one while an on-board EMT propulsion device is limited in size and weight because of restricted hull space. Now, EMT propulsion units are unsatisfactory with respect to size, weight, thrust force and high magnetic field. In view of this, there is an important technological desire to develop EMTs for practical use.